A method for treating ammonia nitrogen wastewater by enriching dominant microorganisms

Abstract

This invention provides a method for treating ammonia nitrogen wastewater by enriching dominant microorganisms. The method efficiently treats ammonia nitrogen wastewater by enriching Acidobacteria and Aerobacteria in an integrated submerged biological filter (SBAF reactor). The method includes the following steps: sludge inoculation, sludge biofilm formation, system startup, and stable operation. During system startup, the distribution of the microbial community in the sludge of the SBAF reactor is used as an indicator of successful startup, and the operating parameters are controlled accordingly. During stable operation, the average removal rate of ammonia nitrogen is 96.5%, and the average removal rate of total nitrogen is 89.4%. Even in the event of a sudden event causing the ammonia nitrogen wastewater concentration to exceed 500 mg / L, the method of treating ammonia nitrogen wastewater by enriching dominant microorganisms can still operate normally, ensuring the removal efficiency of ammonia nitrogen and total nitrogen, and avoiding system collapse and failure to meet the required removal efficiency caused by sudden high concentrations of ammonia nitrogen.

Description

Technical Field

[0001] This invention relates to the field of ammonia nitrogen wastewater treatment, and specifically to a method for treating ammonia nitrogen wastewater by enriching dominant microorganisms. Background Technology

[0002] The pharmaceutical, chemical, fertilizer, petrochemical, coking, smelting, and slaughtering industries are major contributors to ammonia nitrogen wastewater discharge in my country. This wastewater is characterized by a low C / N ratio, making it one of the more difficult types of industrial wastewater to treat. Traditional nitrification-denitrification biological denitrification technologies for treating this type of wastewater face both macroscopic and microscopic technical and economic bottlenecks.

[0003] At a macroscopic level, the nitrification-denitrification process operates in two independent reactors: the first reactor handles nitrification (e.g., reaction 1), and the second reactor handles denitrification (e.g., reaction 2). In the first reactor, nitrification, under aerobic conditions, consumes a large amount of dissolved oxygen to convert all ammonia nitrogen into nitrate nitrogen. Furthermore, due to the generation of hydrogen ions, a significant amount of alkalinity is required to maintain the acid-base balance within the reaction system. Simultaneously, the production of aerobic sludge is substantial. Therefore, this stage presents technical challenges related to high energy and chemical consumption and high sludge production. In the second reactor, denitrification, under anaerobic conditions, consumes a large amount of organic carbon sources and hydrogen ions (which is clearly unsuitable for treating ammonia nitrogen wastewater with a low C / N ratio) to convert nitrate nitrogen into nitrogen gas. Carbon dioxide is also produced as a byproduct. Therefore, this stage suffers from high organic carbon source and chemical consumption and the generation of greenhouse gases.

[0004]

[0005]

[0006] At the microscopic level, in the first reactor, the main functional bacteria for nitrification are nitrifying bacteria, which mainly belong to several phyla, including Proteobacteria. These microorganisms are autotrophic bacteria and are quite sensitive to environmental factors, such as dissolved oxygen concentration >2 mg / L, alkalinity reaching 7.14 g / g (based on 1 g N nitrification), pH between 8.0 and 8.4 (pH changes have a significant impact on nitrifying bacteria), reaction temperature between 20 and 30℃, organic matter concentration not being too high (nitrifying bacteria are autotrophic, and higher organic matter concentrations limit their proliferation), sludge age of 3 days, and very low heavy metal content. In the second reactor, the main functional bacteria for denitrification are denitrifying bacteria. These microorganisms are heterotrophic bacteria, and their environmental requirements differ significantly from those of autotrophic nitrifying bacteria. They require a high organic carbon source (BOD5 / TKN > 3-5, which is clearly unsuitable for treating ammonia nitrogen wastewater with a low C / N ratio), a pH value of 6.5-7.5, dissolved oxygen < 0.5 mg / L, and a reaction temperature of 20-40℃. Therefore, to maintain good survival and reproduction of both types of bacteria, they must be acclimatized and operated in two different reactors. This results in a longer process flow for the nitrification-denitrification method, leading to higher infrastructure investment and operating costs.

[0007] Existing technologies include integrated single-stage autotrophic nitrogen removal methods that utilize functional bacteria (both aerobic and anaerobic ammonia oxidizing bacteria) in a single-stage reactor to achieve nitrogen removal. However, these existing integrated single-stage autotrophic nitrogen removal methods treat ammonia nitrogen wastewater at low concentrations, only 100-200 mg NH4. + The concentration of -N / L water is at most 300 mg / L. Therefore, when encountering sudden high-concentration ammonia nitrogen wastewater pollution, the existing integrated single-stage autotrophic denitrification method cannot cope with sudden high-concentration pollution events. The removal rate of ammonia nitrogen and total nitrogen cannot meet the requirements, the system collapses, or it is necessary to dilute the high-concentration ammonia nitrogen wastewater to an influent concentration of 100~200 mg / L and then treat it through the integrated single-stage autotrophic denitrification method, which increases the total amount of ammonia nitrogen wastewater and wastes water resources due to dilution. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for treating ammonia nitrogen wastewater by enriching dominant microorganisms.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for treating ammonia nitrogen wastewater by enriching dominant microorganisms, wherein the microbial denitrification treatment method includes the following steps:

[0010] (1) The seed mud after air aeration is inoculated into an integrated submerged biological filter. The microbial community in the seed mud includes: Acidobacteria with an abundance of 12.03%~13.03%, Actinobacteria with an abundance of 4.24%~4.58%, Bacteroidetes with an abundance of 19.95%~21.61%, Chlorobi with an abundance of 1.93%~2.09%, and green swollen bacteria. The abundance of Chloroflexi ranged from 13.83% to 14.97%, Firmicutes from 12.59% to 13.64%, Gemmatimonadetes from 3.17% to 3.43%, Proteobacteria from 22.91% to 24.82%, and Verrucomicrobia from 2.36% to 2.55%.

[0011] (2) Inert gas is introduced into the integrated submerged biological filter to carry out biofilm formation. The sludge color changes from yellowish brown (PGB(115,74,18)) to dark brown (PGB(41,36,33)). After stopping the inert gas introduction and letting it stand, the excess sludge is discharged.

[0012] (3) Simulated ammonia nitrogen wastewater is introduced into the reaction system of the integrated submerged biological filter while micro-aeration is performed to start the system. The DO value in the reaction system is controlled at 0.60~0.80 mg / L, the pH value at 6.67-8.01, the water temperature at 29.5-31.9℃, and the hydraulic retention time at 17.5~18.5h. The parameters of the simulated ammonia nitrogen wastewater include pH 7.99~8.35, CODcr 0.0~7.0 mg / L, and NH4+. + -N 102.0-164.0 mg / L, NO2--N 0.0-7.0 mg / L, NO3--N 1.8-3.0 mg / L; the simulated ammonia nitrogen wastewater also contains trace elements iron, manganese, copper, zinc, and cobalt. Multiple batches of simulated wastewater were input, and the system successfully started when the microbial community in the activated sludge of the integrated submerged biological filter met the following conditions;

[0013] The microbial community in the activated sludge of the integrated submerged biological filter includes the following microorganisms in abundance: Acidobacteria (42.57%–45.20%), Chlorobi (17.17%–18.23%), Chloroflexi (4.74%–5.03%), Euryarchaeota (4.01%–4.25%), Firmicutes (1.72%–1.82%), Gemmatimonadetes (1.12%–1.18%), Proteobacteria (14.26%–15.14%), and Verrucomicrobia (8.65%–9.19%).

[0014] (4) Input the ammonia nitrogen wastewater to be treated into the integrated submerged biological filter that was successfully started in step (3) and run it stably.

[0015] While researching methods for treating medium-to-high concentration ammonia nitrogen wastewater by enriching dominant microorganisms in an integrated submerged biological filter (SBAF reactor), the inventors discovered that existing integrated single-stage autotrophic denitrification methods treat ammonia nitrogen wastewater at low concentrations, only 100-200 mg NH4. +The concentration of -N / L in the water means that existing integrated single-stage autotrophic denitrification methods cannot cope with sudden high concentrations of ammonia nitrogen wastewater. The removal rates of ammonia nitrogen and total nitrogen fail to meet requirements, leading to system failure. The inventors, through research, controlled the distribution of microbial communities in the inoculated sludge and the operating parameters during startup of the integrated single-stage autotrophic denitrification method. Specifically, during startup, the microbial community in the activated sludge of the integrated submerged biological filter included the following abundances: Acidobacteria (42.57%–45.20%), Chlorobi (17.17%–18.23%), Chloroflexi (4.74%–5.03%), and Euryarchaeophytes (…). The abundance of microbial communities in activated sludge in an integrated submerged biological filter was 4.01%–4.25%, Firmicutes 1.72%–1.82%, Gemmatimonadetes 1.12%–1.18%, Proteobacteria 14.26%–15.14%, and Verrucomicrobia 8.65%–9.19%. Meeting these conditions was considered a successful start-up indicator. After successful start-up, NH4+ could be treated. + For medium-to-high concentration ammonia nitrogen wastewater with a nitrogen concentration of 100-600 mg / L, this invention's microbial denitrification treatment method for ammonia nitrogen wastewater can still operate normally even if a sudden event causes the ammonia nitrogen wastewater concentration to exceed 500 mg / L, ensuring the removal efficiency of ammonia nitrogen and total nitrogen. This avoids system collapse and failure to meet the removal efficiency requirements caused by sudden high-concentration ammonia nitrogen pollution events, and also avoids the waste of water resources caused by diluting high-concentration ammonia nitrogen wastewater to adapt to low-concentration ammonia nitrogen treatment methods.

[0016] Preferably, in step (1), the microbial community in the seed mud includes: Acidobacteria with an abundance of 12.53%, Actinobacteria with an abundance of 4.41%, Bacteroidetes with an abundance of 20.78%, Chlorobi with an abundance of 2.01%, Chloroflexi with an abundance of 14.4%, Firmicutes with an abundance of 13.12%, Gemmatimonadetes with an abundance of 3.3%, Proteobacteria with an abundance of 23.87%, and Verrucomicrobia with an abundance of 2.46%.

[0017] Preferably, in step (1), the sludge concentration of the seed mud after air aeration is 16800~21000 mg / L, the MLSS of the seed mud after air aeration is 10000~11500 mg / L, the MLVSS of the seed mud after air aeration is 3000~3500 mg / L, and the pH of the seed mud is 6.0~7.5.

[0018] The above-mentioned method for treating ammonia nitrogen wastewater by enriching dominant microorganisms can treat wastewater with higher concentrations of ammonia nitrogen.

[0019] Preferably, in step (3), the microbial community in the activated sludge of the integrated submerged biological filter includes the following abundances of microorganisms: Acidobacteria (43.89%), Chlorobi (17.7%), Chloroflexi (4.89%), Euryarchaeota (4.13%), Firmicutes (1.77%), Gemmatimonadetes (1.15%), Proteobacteria (14.7%), and Verrucomicrobia (8.92%).

[0020] The above-mentioned method for treating ammonia nitrogen wastewater by enriching dominant microorganisms can treat wastewater with higher concentrations of ammonia nitrogen.

[0021] Preferably, in step (4), the ammonia nitrogen concentration of the ammonia nitrogen wastewater to be treated is 100~600 mg / L.

[0022] Preferably, in step (4), the ammonia nitrogen concentration of the ammonia nitrogen wastewater to be treated is 500~600 mg / L.

[0023] The above-mentioned microbial denitrification treatment method for ammonia nitrogen wastewater can treat NH4. +This invention provides a stable microbial denitrification treatment method for ammonia nitrogen wastewater with a nitrogen concentration of 100-600 mg / L, ensuring efficient removal of both ammonia nitrogen and total nitrogen. Even in the event of a sudden event causing the ammonia nitrogen concentration to exceed 500 mg / L, the method can still operate normally, guaranteeing the removal efficiency of both ammonia nitrogen and total nitrogen. This avoids system collapse and failure to meet removal efficiency requirements due to sudden high-concentration ammonia nitrogen pollution, and eliminates the need to dilute high-concentration ammonia nitrogen wastewater to accommodate lower-concentration methods, thus preventing water waste. Furthermore, for ammonia nitrogen wastewater with a concentration of 100-600 mg / L, the ammonia nitrogen conversion rate is 91.2%-100.0%, with an average conversion rate of 96.5%; the total nitrogen removal rate is 77.0%-99.1%, with an average removal rate of 89.4%.

[0024] Preferably, in step (4), the DO in the reaction system is controlled at 0.6~0.8 mg / L, the pH value is controlled at 7.01~7.84, the water temperature is controlled at 29.3~32.2℃, and the hydraulic retention time is controlled at 17.5~18.5h.

[0025] Preferably, in step (3), the simulated ammonia nitrogen wastewater comprises the following components: NH4Cl 0.38~2.30 g / L, KH2PO4·3H2O 0.05~0.3 g / L, MgSO4 0.02~0.12 g / L, CaCl2 0.02~0.12 g / L, NaHCO3 0.20~1.20 g / L. The simulated ammonia nitrogen wastewater also contains 0.20~0.40 ml / L of a trace element solution. The components and concentrations of the trace element solution are: FeCl3·6H2O 3.00~3.50 g / L, MnCl2·4H2O 0.30~0.40 g / L, CuSO4·5H2O 0.07~0.08 g / L, ZnSO4·7H2O 0.02~0.30 g / L, and CoCl2·6H2O. 0.30~0.40 g / L.

[0026] Preferably, in step (2), the ratio of the amount of biofilm seed mud used to the effective volume of the integrated submerged biological filter is 1:2.

[0027] Preferably, in step (2), the inert gas is nitrogen or helium, the inert gas pressure is controlled at 0.20~0.25 MPa, the continuous ventilation time is 18~24 h, and the settling time after ventilation is 0.8~1.2 h.

[0028] Preferably, the integrated submerged biological filter is equipped with a combined packing material, which consists of three parts: a packing disc, a plastic sleeve, and a central copper wire tube. The structure of the combined packing material is to press the plastic disc into a double-ring large plastic ring, and press the polyester filaments on the ring of the double-ring large plastic ring to make the fiber bundles evenly distributed; the inner ring of the double-ring large plastic ring is a snowflake-shaped plastic branch.

[0029] The aforementioned method for efficiently treating ammonia nitrogen wastewater by enriching dominant microorganisms involves using a combined packing material in an integrated submerged biological filter. This material can both support biofilm formation and effectively cut air bubbles, thereby improving the oxygen transfer rate and utilization rate. As a result, the water-air biofilm undergoes sufficient exchange, leading to efficient treatment of nitrogen in the water.

[0030] Preferably, in step (3), the bottom sediment is not discharged; in step (4), the bottom sediment is not discharged.

[0031] Preferably, in step (4), the stable operation time is 50 to 200 days.

[0032] The beneficial effects of this invention are as follows: This invention provides a method for efficiently treating ammonia nitrogen wastewater by enriching dominant microorganisms. This method controls the community distribution of microorganisms in the inoculated sludge and the operating parameters during startup of the integrated single-stage autotrophic denitrification method. Specifically, during startup, the abundance of the microbial community in the activated sludge of the integrated submerged biological filter meets the above conditions as a sign of successful startup. After successful startup, it can treat NH4+. + For medium-to-high concentration ammonia nitrogen wastewater with a nitrogen concentration of 100-600 mg / L, the microbial denitrification treatment method for ammonia nitrogen wastewater of this invention can still operate normally even when the concentration of ammonia nitrogen wastewater exceeds 500 mg / L due to a sudden event. This ensures the removal efficiency of ammonia nitrogen and total nitrogen, avoids system collapse caused by sudden high concentrations of ammonia nitrogen and failure to meet the removal efficiency requirements of ammonia nitrogen and total nitrogen, and eliminates the need to dilute the high concentration of ammonia nitrogen wastewater to adapt to the waste of water resources caused by the treatment method.

[0033] The differences and advantages of this invention's efficient treatment of ammonia nitrogen wastewater using enriched dominant microorganisms compared to conventional technologies:

[0034] (1) Superior overall process performance. Conventional biological nitrogen removal technology adopts a combined nitrification-denitrification method, which operates in two different reactors. In actual sludge acclimation and operation, the environmental conditions of different reactors vary greatly, and there are conventional problems such as good nitrification effect but limited denitrification capacity, long process flow, large oxygen consumption and organic carbon source demand, and high residual sludge production, which limit the treatment effect of the integrated nitrification-denitrification biochemical technology on wastewater containing ammonia nitrogen. The integrated SABF reactor selected in this invention enriches acidobacteria and can effectively remove ammonia nitrogen and total nitrogen in the same reactor. It can treat high-concentration ammonia nitrogen wastewater and save 62.5% of oxygen consumption, 100% of organic carbon source and 50% of alkali consumption, halve the process flow, and reduce sludge production by 90%. These all demonstrate the technical and economic advantages of this biological nitrogen removal method.

[0035] (2) Effective Improvement of Nitrogen Removal Performance. Conventional nitrification-denitrification biological nitrogen removal systems, during startup and operation, employ methods such as controlling temperature, dissolved oxygen, influent ammonia nitrogen load, and hydraulic retention time to achieve an ammonia nitrogen conversion rate of 91.2%–100.0% and a total nitrogen removal rate of 77.0%–99.1%. Based on this, the present invention adjusts parameters such as temperature, dissolved oxygen, pH, and hydraulic retention time during the system startup and stable operation phases, without requiring sludge discharge throughout the entire process. During startup, the ammonia nitrogen conversion rate increases from 20.0% to 100.0%, and the total nitrogen removal rate increases from 0.0% to 78.0%. During operation, the ammonia nitrogen conversion rate ranges from 91.2% to 100.0%, with an average conversion rate of 95.6%, and the total nitrogen removal rate ranges from 77.0% to 99.1%, with an average removal rate of 89.4%. This demonstrates the superiority of the present invention.

[0036] (3) Effective suppression of reaction byproducts. In traditional nitrification-denitrification biological denitrification, the growth and accumulation of nitrifying bacteria are affected by the presence of free ammonia and free imine during operation, resulting in incomplete nitrification and affecting the ammonia nitrogen removal performance of the reaction system. The technology of this invention adjusts the parameters of temperature, dissolved oxygen, pH, and hydraulic retention time in the system during the start-up and stable operation stages, respectively. This can effectively stabilize the activity and growth of aerobic nitrite-oxidizing bacteria and nitrifying bacteria, and improve the average ammonia nitrogen removal rate, which has a significant promoting effect on improving the performance of biological denitrification.

[0037] (4) Saving of organic carbon source. In the traditional nitrification-denitrification biological nitrogen removal process, the denitrification stage requires a large amount of organic carbon source to ensure the normal growth and reproduction of denitrifying bacteria and ensure the efficient operation of denitrification. The technology of this invention does not require the addition of an additional organic carbon source to ensure the effective growth and reproduction of Acidobacteris, ensuring the smooth operation of denitrification, thereby stabilizing the total nitrogen removal performance.

[0038] (5) Effective Expansion of Technology Application. Traditional nitrification-denitrification biological nitrogen removal requires strict control of key conditions such as temperature, dissolved oxygen, influent ammonia nitrogen load, and hydraulic retention time within very narrow threshold ranges during startup and operation. This places high demands on the design precision of automatic control equipment and the skill level of operators in practical engineering. The technology of this invention addresses the different requirements for the range of condition parameters during the two different stages of system startup and stable operation by adjusting the parameters of temperature, dissolved oxygen, pH, and hydraulic retention time within the system (with a certain expansion of the threshold range) to improve the nitrogen removal performance of the reaction system. This has a more practical and effective feasibility for the design and control of automatic control equipment and the skill level of operators in practical engineering, thus further facilitating the widespread application of this technology.

[0039] (6) Optimization of technical operating costs. During startup and operation, the technology of this invention can effectively save on civil engineering costs (halving the process flow), reduce oxygen consumption and energy costs by 62.5%, save 100% of organic carbon sources and 50% of alkali consumption, and reduce sludge production by 90%. In addition to the above advantages, the technology of this invention also produces extremely low sludge during startup and operation, and there is no need to remove excess sludge throughout the entire process. Attached Figure Description

[0040] Figure 1 This is a diagram showing the abundance of microbial communities in the inoculated sludge used in the method for treating ammonia nitrogen wastewater by enriching dominant microorganisms according to the present invention.

[0041] Figure 2 This is a diagram showing the abundance of sludge microbial communities when the system is successfully started up in the method for treating ammonia nitrogen wastewater by enriching dominant microorganisms according to the present invention.

[0042] Figure 3 This figure shows the stable operation results of the method for treating ammonia nitrogen wastewater by enriching dominant microorganisms according to the present invention. Detailed Implementation

[0043] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0044] Example 1

[0045] As an embodiment of the present invention, a method for treating ammonia nitrogen wastewater by enriching dominant microorganisms includes the following steps:

[0046] (1) The seed mud after air aeration was inoculated into an integrated submerged biological filter. The microbial community in the seed mud included: Acidobacteria with an abundance of 12.03%~13.03%, Actinobacteria with an abundance of 4.24%~4.58%, Bacteroidetes with an abundance of 19.95%~21.61%, Chlorobi with an abundance of 1.93%~2.09%, and Chloroflexi with an abundance of 1.93%~2.09%. The abundance of the following phyla was 13.83%–14.97%, Firmicutes 12.59%–13.64%, Gemmatimonadetes 3.17%–3.43%, Proteobacteria 22.91%–24.82%, and Verrucomicrobia 2.36%–2.55%. The sludge concentration of the seed sludge after air aeration was 16,800–21,000 mg / L, the MLSS of the seed sludge after air aeration was 10,000–11,500 mg / L, the MLVSS of the seed sludge after air aeration was 3,000–3,500 mg / L, and the pH of the seed sludge was 6.0–7.5.

[0047] (2) Inert gas is introduced into the integrated submerged biological filter to carry out biofilm formation. The sludge color changes from yellowish brown to dark brown. After stopping the inert gas introduction and letting it stand, the excess sludge is discharged.

[0048] (3) Simulated ammonia nitrogen wastewater is introduced into the reaction system of the integrated submerged biological filter while micro-aeration is performed to start the system. The DO value in the reaction system is controlled at 0.65~0.75 mg / L, the pH value at 7.5~7.8, the average water temperature at 30~31℃, and the hydraulic retention time at 17.5~18.5h. The parameters of the simulated ammonia nitrogen wastewater include pH 8.0~8.30, CODcr 0.0~6.0 mg / L, and NH4+. + -N 102.0-165.0 mg / L, NO2--N 0.0-7.0 mg / L, NO3--N1.8-3.0 mg / L;

[0049] The simulated ammonia nitrogen wastewater also contains trace elements such as iron, manganese, copper, zinc, and cobalt. Multiple batches of simulated wastewater are input, and the system starts successfully when the microbial community in the activated sludge of the integrated submerged biological filter meets the following conditions.

[0050] The microbial community in the activated sludge of the integrated submerged biological filter includes the following microorganisms in abundance: Acidobacteria (42.57%–45.20%), Chlorobi (17.17%–18.23%), Chloroflexi (4.74%–5.03%), Euryarchaeota (4.01%–4.25%), Firmicutes (1.72%–1.82%), Gemmatimonadetes (1.12%–1.18%), Proteobacteria (14.26%–15.14%), and Verrucomicrobia (8.65%–9.19%).

[0051] (4) Input the ammonia nitrogen wastewater to be treated into the integrated submerged biological filter that was successfully started in step (3) and run it stably. The DO in the reaction system is controlled at 0.6~0.8 mg / L, the pH value is controlled at 7.01~7.84, the water temperature is controlled at 29.3-32.2 ℃, and the hydraulic retention time is 18 h.

[0052] Trial run

[0053] The process flow of this invention is as follows:

[0054] (a) Seed sludge preparation: Ordinary activated sludge from the secondary sedimentation tank of a municipal wastewater treatment plant, light yellowish-brown in color, was taken. After settling for 0.5 hours, it was aerated for 12 hours. The seed sludge had a pH of 6.6, MLSS of 10500 mg / L, MLVSS of 3200 mg / L, and a sludge concentration of 17800 mg / L. The distribution of the microbial community in the seed sludge was analyzed as follows: Figure 1 As shown, 2.8 L of sludge was poured into a submerged biological filter (SBAF) reactor with a suspended combined packing material and an effective volume of 3.2 L. The actual amount (volume) of sludge used for biofilm formation was 1:2 compared with the effective volume of the reactor.

[0055] (b) Biofilm formation: Pure nitrogen gas is introduced into the bottom of the SBAF reactor at a pressure controlled within the range of 0.20-0.25 MPa for 18 hours. The sludge in the SBAF reactor gradually adheres to the surface of the combined packing material. The combined packing material consists of three parts: packing discs, plastic sleeves, and central copper wire. The structure of the combined packing material is to press plastic discs into double-ring large plastic rings and press polyester filaments onto the rings of the double-ring large plastic rings to make the fiber bundles evenly distributed. The inner ring of the double-ring large plastic rings consists of snowflake-shaped plastic branches. When the sludge color changes from yellowish-brown to dark brown, the nitrogen gas is stopped and the mixture is allowed to stand for 1 hour. The remaining sludge is then discharged from the sludge discharge port at the bottom of the SBAF reactor.

[0056] (c) Simulated ammonia nitrogen wastewater is introduced into the reaction system of the integrated submerged biological filter to start the system with micro-aeration. Micro-aeration is performed from the bottom of the reactor. The parameters of the simulated ammonia nitrogen wastewater include pH 7.99~8.36, CODcr 0.0~7.0 mg / L, and NH4+. +The simulated ammonia nitrogen wastewater comprises the following components: NH4Cl 0.40~0.63 g / L, KH2PO4·3H2O 0.00~0.03 g / L, MgSO4 0.01~0.02 g / L, CaCl2 0.01~0.02 g / L, NaHCO3 0.20~1.00 g / L. The simulated ammonia nitrogen wastewater also contains 0.10~0.15 ml / L of a trace element solution, the composition and concentration of which are FeCl3·6H2O 3.00~3.50 g / L, MnCl2·4H2O 0.30~0.40 g / L, and CuSO4·5H2O. 0.07~0.08 g / L, ZnSO4·7H2O 0.02~0.30 g / L, CoCl2·6H2O 0.30~0.40 g / L. The DO value in the reaction system was controlled at 0.6-0.8 mg / L, pH at 6.67-8.01, water temperature at 29.5-31.9 ℃, and hydraulic retention time at 18... h; A small amount of sludge was collected from the submerged biological filter (SBAF) reactor, and the abundance of microbial communities in the sludge was detected. The microbial community in the activated sludge of the integrated submerged biological filter included the following microorganisms with the following abundances: Acidobacteria (42.57%–45.20%), Chlorobi (17.17%–18.23%), Chloroflexi (4.74%–5.03%), and Euryarchaeota (…). When the abundance of microorganisms in the activated sludge of the integrated submerged biological filter is 4.01%–4.25%, the abundance of Firmicutes is 1.72%–1.82%, the abundance of Gemmatimonadetes is 1.12%–1.18%, the abundance of Proteobacteria is 14.26%–15.14%, and the abundance of Verrucomicrobia is 8.65%–9.19%, it indicates that the system has started successfully. The abundance of microbial communities in the activated sludge of the integrated submerged biological filter is as follows: Figure 2 As shown;

[0057] (d) Input the ammonia nitrogen wastewater to be treated, NH4 + The -N concentration was stable at 102-619 mg / L, the DO concentration in the reaction system was controlled at 0.6-0.8 mg / L, the pH value was controlled at 5.3-8.32, the water temperature was controlled at 29.3-32.2 ℃, and the hydraulic retention time was 18h.

[0058] During the experiment, the parameters of the simulated ammonia nitrogen wastewater to be treated included pH 7.60~8.76, CODcr 0.0~16.0 mg / L, and NH4+. + The simulated ammonia nitrogen wastewater to be treated comprises the following components: NH4Cl 0.63~2.37 g / L, KH2PO4·3H2O 0.02~0.30 g / L, MgSO4 0.02~0.12 g / L, CaCl2 0.02~0.12 g / L, NaHCO3 0.20~1.20 g / L. The simulated ammonia nitrogen wastewater also contains 0.20~0.40 ml / L of trace element solution, wherein the components and concentrations of the trace element solution are FeCl3·6H2O 3.00~3.50 g / L, MnCl2·4H2O 0.30~0.40 g / L, and CuSO4·5H2O. 0.07~0.08 g / L, ZnSO4·7H2O 0.02~0.30g / L, CoCl2·6H2O 0.30~0.40 g / L.

[0059] In step (4) above, the simulated ammonia nitrogen wastewater to be treated is input during the experimental process for experimental research. Those skilled in the art will understand that in actual operation, the ammonia nitrogen wastewater to be treated with a concentration of 100~600 mg / L is input in step (4).

[0060] The results of the invention's operation are shown in Tables 2 and 3. Figure 3 As shown, the system is started. From day 1 to day 6, the sludge is in the initial inoculation stage. Low DO severely inhibits the activity of aerobic ammonia-oxidizing bacteria and nitrifying bacteria, resulting in only a portion of NH4+ being produced. + -N can be oxidized, producing NH4 in the effluent. + The effluent NO₂⁻ concentration ranged from 72.0 to 96.0 mg / L, with an average concentration of 88.3 mg / L; the effluent NO₂⁻ concentration ranged from 4.0 to 35.0 mg / L, with an average concentration of 17.0 mg / L; and the effluent NO₃⁻ concentration ranged from 1.4 to 4.9 mg / L, with an average concentration of 2.3 mg / L. From days 7 to 19, a large number of aerobic ammonia-oxidizing bacteria accumulated in the system, while a small number of nitrifying bacteria were present, leading to an increase in effluent NH₄⁺. + -N concentration decreased from 96.0 mg / L to 52.0 mg / L, and NO2 in the effluent decreased. - -N concentration increased from 48.0 mg / L to 90.0 mg / L; effluent NO3 -The -N concentration increased slightly from 1.9 mg / L to 7.5 mg / L, indicating that nitrifying bacteria could be effectively inhibited. From day 20 to 51, the system continued to enrich aerobic ammonia-oxidizing bacteria and began to enrich denitrifying bacteria, causing denitrification. The effluent NH4+ concentration increased significantly. + -N concentration decreased from 52.0 mg / L to 12.0 mg / L, and NO2 in the effluent decreased. - -N concentration decreased from 59.0 mg / L to 20.0 mg / L. Meanwhile, the effluent NO3 concentration decreased. - When the nitrogen concentration is in the range of 0.0~8.8 mg / L, the ammonia nitrogen conversion rate increases from 65.3% to 90.9%, and the total nitrogen removal rate increases from 0.0% to 72.9%, indicating successful initiation of partial nitrification-denitrification. During this period, the reactor operates continuously without sludge discharge.

[0061] Stable operation. After the system entered the operational phase, from day 52 to 232, the influent NH4... + When the ammonia nitrogen concentration is in the range of 102.0~619.0 mg / L, and the ammonia nitrogen concentration gradually increases to above 500 mg / L, a high ammonia nitrogen removal rate can still be achieved; effluent NH4 + -N concentration ranged from 0.0 to 51.0 mg / L, with an average concentration of 13.3 mg / L; effluent NO2 - -N concentration ranged from 0.0 to 17.0 mg / L, with an average concentration of 3.1 mg / L; effluent NH4 + -N and NO2 - -N mass concentration remained consistently low. (Effluent NO3) - The -N concentration ranged from 0.0 to 78.8 mg / L, with an average concentration of 26.4 mg / L, indicating a low nitrifying bacteria content in the system. During this operational phase, the ammonia nitrogen conversion rate ranged from 91.2% to 100.0%, with an average conversion rate of 96.5%; the total nitrogen removal rate ranged from 77.0% to 99.1%, with an average removal rate of 89.4%. Furthermore, no organic carbon source was added during the start-up and operation phases of the reaction system, and the reactor operated continuously and stably without sludge discharge.

[0062] The experimental results show that, during the system startup and stable operation phases, adjusting parameters such as temperature, dissolved oxygen, pH, and hydraulic retention time, and ensuring that the microbial community in the activated sludge of the integrated submerged biological filter meets the set conditions, is the indicator of successful system startup and the ability to treat NH4. +For ammonia nitrogen wastewater with a nitrogen concentration of 100-600 mg / L, even in the event of a sudden event causing the ammonia nitrogen concentration to exceed 500 mg / L, the method of treating ammonia nitrogen wastewater using enriched dominant microorganisms according to this invention can still operate normally, ensuring the removal efficiency of ammonia nitrogen and total nitrogen. This avoids system collapse caused by sudden high concentrations of ammonia nitrogen and failure to meet the required removal efficiency, and eliminates the need to dilute the high-concentration ammonia nitrogen wastewater to accommodate the wastewater treatment method, thus preventing water waste. Furthermore, the system can maintain highly efficient and stable biological nitrogen removal performance without requiring sludge discharge throughout the entire process. The influent and effluent water quality and effluent technical parameters of the wastewater treated by the process of this invention are shown in Tables 1, 2, and 3, respectively.

[0063] Table 1. Influent and effluent water quality and reaction system parameters of the present invention (days 1-51, during system startup)

[0064]

[0065] Table 2. Influent and effluent water quality and reaction system parameters of the present invention (d. 52-232, during stable operation)

[0066]

[0067] Table 3 Comparison of Parameters

[0068]

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for treating ammonia-nitrogen wastewater by enrichment of dominant microorganisms, characterized in that, The method for treating ammonia-nitrogen wastewater by the enriched dominant microorganism comprises the following steps: (1) inoculating seed sludge after air aeration into an integrated submerged biofilter, wherein the microbial community in the seed sludge comprises: the abundance of Acidobacteria is 12.03%~13.03%, the abundance of Actinobacteria is 4.24%~4.58%, the abundance of Bacteroidetes is 19.95%~21.61%, the abundance of Chlorobi is 1.93%~2.09%, the abundance of Chloroflexi is 13.83%~14.97%, the abundance of Firmicutes is 12.59%~13.64%, the abundance of Gemmatimonadetes is 3.17%~3.43%, the abundance of Proteobacteria is 22.91%~24.82%, and the abundance of Verrucomicrobia is 2.36%~2.55%; in the step (1), the sludge concentration of the seed sludge after air aeration is 16800~21000 mg / L, the MLSS of the seed sludge after air aeration is 10000~11500 mg / L, the MLVSS of the seed sludge after air aeration is 3000~3500 mg / L, and the pH of the seed sludge is 6.0~7.5; (2) introducing inert gas into the integrated submerged biofilter to carry out biological membrane forming, and stopping the introduction of inert gas when the color of the sludge changes from yellow brown to black brown, and then discharging the excess sludge after standing; (3) inputting simulated ammonia-nitrogen wastewater into a reaction system of the integrated submerged biofilter while performing micro-aerobic air exposure to start up the system, controlling the DO value in the reaction system to be 0.60-0.80 mg / L, the pH value to be 6.67-8.01, the average water temperature to be controlled at 29.5-31.9 ℃, and the hydraulic retention time to be controlled at 17.5-18.5 h; the parameters of the simulated ammonia-nitrogen wastewater include pH 7.99-8.35, CODcr 0.0-7.0 mg / L, NH4 + -N 102.0-164.0 mg / L, NO2 - -N 0.0-7.0 mg / L, NO3 - -N 1.8-3.0 mg / L; the simulated ammonia-nitrogen wastewater also contains trace elements of iron, manganese, copper, zinc and cobalt, and multiple batches of simulated ammonia-nitrogen wastewater are inputted; when the microbial community in the activated sludge in the integrated submerged biofilter meets the following conditions, the system startup is successful: the abundance of Acidobacteria is 42.57%~45.20%, the abundance of Chlorobi is 17.17%~18.23%, the abundance of Chloroflexi is 4.74%~5.03%, the abundance of Euryarchaeota is 4.01%~4.25%, the abundance of Firmicutes is 1.72%~1.82%, the abundance of Gemmatimonadetes is 1.12%~1.18%, the abundance of Proteobacteria is 14.26%~15.14%, and the abundance of Verrucomicrobia is 8.65%~9.19%; (4) inputting the ammonia-nitrogen wastewater to be treated into the integrated submerged biofilter in which the system is successfully started in the step (3), and stably running, wherein the ammonia-nitrogen concentration of the ammonia-nitrogen wastewater to be treated is 500~600 mg / L.

2. The method of claim 1, wherein the enriched dominant microorganisms are used to treat ammonia-nitrogen wastewater. In the step (1), the microbial community in the seed sludge comprises: the abundance of Acidobacteria is 12.53%, the abundance of Actinobacteria is 4.41%, the abundance of Bacteroidetes is 20.78%, the abundance of Chlorobi is 2.01%, the abundance of Chloroflexi is 14.4%, the abundance of Firmicutes is 13.12%, the abundance of Gemmatimonadetes is 3.3%, the abundance of Proteobacteria is 23.87%, and the abundance of Verrucomicrobia is 2.46%.

3. The method of claim 1, wherein the enriched dominant microorganisms are used to treat ammonia-nitrogen wastewater. In the step (3), the microbial community in the activated sludge in the integrated submerged biofilter comprises the following abundance of microorganisms: the abundance of Acidobacteria is 43.89%, the abundance of Chlorobi is 17.7%, the abundance of Chloroflexi is 4.89%, the abundance of Euryarchaeota is 4.13%, the abundance of Firmicutes is 1.77%, the abundance of Gemmatimonadetes is 1.15%, the abundance of Proteobacteria is 14.7%, and the abundance of Verrucomicrobia is 8.92%.

4. The method of claim 1, wherein the enriched dominant microorganisms are used to treat ammonia-nitrogen wastewater. In the step (4), the DO in the reaction system is controlled at 0.6-0.8 mg / L, the pH value is controlled at 7.01-7.84, the water temperature is controlled at 29.3-32.2℃, and the hydraulic retention time is controlled at 17.5-18.5 h.

5. The method of claim 1, wherein the enriched dominant microorganisms are used to treat ammonia-nitrogen wastewater. In the step (3), the simulated ammonia-nitrogen wastewater comprises the following components: NH4Cl 0.40-0.63 g / L, KH2PO4·3H2O 0.00-0.03 g / L, MgSO4 0.01-0.02 g / L, CaCl2 0.01-0.02 g / L, NaHCO3 0.20-1.00 g / L, trace element solution 0.10-0.15 ml / L, wherein the trace element solution comprises FeCl3·6H2O 3.00-3.50 g / L, MnCl2·4H2O 0.30-0.40 g / L, CuSO4·5H2O 0.07-0.08 g / L, ZnSO4·7H2O 0.02-0.30 g / L, and CoCl2·6H2O 0.30-0.40 g / L.

6. The method of claim 1, wherein the enriched dominant microorganisms are used to treat ammonia-nitrogen wastewater. In the step (2), the ratio of the amount of the seed sludge to the effective volume of the integrated submerged biofilter is 1:

2.

7. The method of claim 1, wherein the enriched dominant microorganisms are used to treat ammonia-nitrogen wastewater. In the step (2), the inert gas is nitrogen or helium, the gas pressure of the inert gas is controlled at 0.20-0.25 Mpa, the duration of the aeration is 18-24 h, and the standing time after the aeration is 0.8-1.2 h. The integrated submerged biofilter is provided with a combined filler, which comprises a filler single piece, a plastic sleeve and a central copper tube wire, and the structure of the combined filler is that a plastic round piece is pressed into a double-circle large plastic ring, and polyester wire is pressed on the ring of the double-circle large plastic ring to make the fiber bundle uniformly distributed; the inner circle of the double-circle large plastic ring is a snowflake-shaped plastic branch.

8. The method of claim 1, wherein the enriched dominant microorganisms are used to treat ammonia-nitrogen wastewater. In the step (3), the bottom mud is not discharged; and in the step (4), the bottom mud is not discharged.

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